/** @file
  Helper Routines that use a PXE-enabled NIC option ROM.

Copyright (c) 1999 - 2018, Intel Corporation. All rights reserved.<BR>

SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "BiosSnp16.h"

#define TO_SEGMENT(x)   ((UINT16) (RShiftU64 ((UINT32)(UINTN) (x), 4) & 0xF000))
#define TO_OFFSET(x)    ((UINT16) ((UINT32)(UINTN) (x) & 0xFFFF))
#define PARAGRAPH_SIZE  0x10
#define IVT_BASE        0x00000000

#pragma pack(1)
typedef struct {
  UINT16  Signature;          ///< 0xaa55
  UINT8   ROMlength;          ///< size of this ROM in 512 byte blocks
  UINT8   InitEntryPoint[4];  ///< a jump to the initialization routine
  UINT8   Reserved[0xf];      ///< various
  UINT16  PxeRomIdOffset;     ///< offset of UNDI, $BC$, or BUSD ROM ID structure
  UINT16  PcirHeaderOffset;   ///< offset of PCI Expansion Header
  UINT16  PnpHeaderOffset;    ///< offset of Plug and Play Expansion Header
} OPTION_ROM_HEADER;
#pragma pack()

UINT32 CachedVectorAddress[0x100];

/**
 Cache Interrupt verctor address converted from IVT number.

 @param VectorNumber  IVT number

 @retval EFI_SUCCESS Success to operation.
**/
EFI_STATUS
CacheVectorAddress (
  UINT8   VectorNumber
  )
{
  UINT32  *Address;

  Address                          = (UINT32 *) ((UINTN) IVT_BASE + VectorNumber * 4);
  CachedVectorAddress[VectorNumber] = *Address;
  return EFI_SUCCESS;
}

/**
 Get interrupt vector address according to IVT number.

 @param VectorNumber    Given IVT number

 @return cached interrupt vector address.
**/
EFI_STATUS
RestoreCachedVectorAddress (
  UINT8   VectorNumber
  )
{
  UINT32  *Address;

  Address  = (UINT32 *) ((UINTN) IVT_BASE + VectorNumber * 4);
  *Address = CachedVectorAddress[VectorNumber];
  return EFI_SUCCESS;
}

/**
 Print Undi loader table.

 @param UndiLoaderStructure Point to Undi Loader table structure.

**/
VOID
Print_Undi_Loader_Table (
  VOID *UndiLoaderStructure
  )
{
  UNDI_LOADER_T *DisplayPointer;

  DisplayPointer = (UNDI_LOADER_T *) UndiLoaderStructure;

  DEBUG ((DEBUG_NET, "Before Parsing the table contents, the table itself lives\n"));
  DEBUG ((DEBUG_NET, "\tat the address 0x%X\n\r", (UINT32)(UINTN) UndiLoaderStructure));

  DEBUG ((DEBUG_NET, "\n\rStatus = 0x%X\n\r", DisplayPointer->Status));
  DEBUG ((DEBUG_NET, "\t_AX_= 0x%X\n\r", DisplayPointer->Ax));
  DEBUG ((DEBUG_NET, "\t_BX_= 0x%X\n\r", DisplayPointer->Bx));
  DEBUG ((DEBUG_NET, "\t_DX_= 0x%X\n\r", DisplayPointer->Dx));
  DEBUG ((DEBUG_NET, "\t_DI_= 0x%X\n\r", DisplayPointer->Di));
  DEBUG ((DEBUG_NET, "\t_ES_= 0x%X\n\r", DisplayPointer->Es));
  DEBUG ((DEBUG_NET, "\tUNDI_DS= 0x%X\n\r", DisplayPointer->Undi_Ds));
  DEBUG ((DEBUG_NET, "\tUNDI_CS= 0x%X\n\r", DisplayPointer->Undi_Cs));
  DEBUG ((DEBUG_NET, "\tPXEptr:SEG= 0x%X\n\r", (UINT16) DisplayPointer->PXEptr.Segment));
  DEBUG ((DEBUG_NET, "\tPXEptr:OFF= 0x%X\n\r", (UINT16) DisplayPointer->PXEptr.Offset));
  DEBUG ((DEBUG_NET, "\tPXENVptr:SEG= 0x%X\n\r", (UINT16) DisplayPointer->PXENVptr.Segment));
  DEBUG ((DEBUG_NET, "\tPXENVptr:OFF= 0x%X\n\r", (UINT16) DisplayPointer->PXENVptr.Offset));
}

/**
  Simple table dumper.  The ROMID table is necessary in order to effect
  the "Early UNDI" trick.  Herein, the UNDI layer can be loaded in the
  pre-boot phase without having to download a Network Boot Program
  across the wire.  It is required in the implementation in that we
  are not using PXE.

  @param RomIDStructure Point to RomID structure.

**/
VOID
Print_ROMID_Table (
  IN VOID *RomIDStructure
  )
{
  UNDI_ROMID_T  *DisplayPointer;

  DisplayPointer = (UNDI_ROMID_T *) RomIDStructure;

  DEBUG ((DEBUG_NET, "Before Parsing the table contents, the table itself lives\n"));
  DEBUG ((DEBUG_NET, "\tat the address 0x%X\n\r", (UINT32)(UINTN) RomIDStructure));

  DEBUG (
    (DEBUG_NET,
    "\n\rROMID %c%c%c%c\n\r",
    DisplayPointer->Signature[0],
    DisplayPointer->Signature[1],
    DisplayPointer->Signature[2],
    DisplayPointer->Signature[3])
    );

  DEBUG (
    (DEBUG_NET,
    "Length of this structure in bytes = 0x%X\n\r",
    DisplayPointer->StructLength)
    );
  DEBUG (
    (DEBUG_NET,
    "Use to make byte checksum of this structure == zero is = 0x%X\n\r",
    DisplayPointer->StructCksum)
    );
  DEBUG (
    (DEBUG_NET,
    "Structure format revision number= 0x%X\n\r",
    DisplayPointer->StructRev)
    );
  DEBUG (
    (DEBUG_NET,
    "API Revision number = 0x%X 0x%X 0x%X\n\r",
    DisplayPointer->UNDI_Rev[0],
    DisplayPointer->UNDI_Rev[1],
    DisplayPointer->UNDI_Rev[2])
    );
  DEBUG (
    (DEBUG_NET,
    "Offset of UNDI loader routine in the option ROM image= 0x%X\n\r",
    DisplayPointer->UNDI_Loader)
    );
  DEBUG ((DEBUG_NET, "From the data above, the absolute entry point of the UNDI loader is\n\r"));
  DEBUG (
    (DEBUG_NET,
    "\tat address 0x%X\n\r",
    (UINT32) (DisplayPointer->UNDI_Loader + ((UINT32) (UINTN)(DisplayPointer - 0x20) & 0xFFFF0)))
    );
  DEBUG ((DEBUG_NET, "Minimum stack segment size, in bytes,\n\r"));
  DEBUG (
    (DEBUG_NET,
    "needed to load and run the UNDI= 0x%X \n\r",
    DisplayPointer->StackSize)
    );
  DEBUG (
    (DEBUG_NET,
    "UNDI runtime code and data = 0x%X\n\r",
    DisplayPointer->DataSize)
    );
  DEBUG (
    (DEBUG_NET,
    "Segment size = 0x%X\n\r",
    DisplayPointer->CodeSize)
    );
  DEBUG (
    (DEBUG_NET,
    "\n\rBus Type =  %c%c%c%c\n\r",
    DisplayPointer->BusType[0],
    DisplayPointer->BusType[1],
    DisplayPointer->BusType[2],
    DisplayPointer->BusType[3])
    );
}

/**
  Print PXE table.

  @param PxeTable Point to PXE table structure

**/
VOID
Print_PXE_Table (
  IN VOID*  PxeTable
  )
{
  PXE_T *DisplayPointer;
  UINTN Index;
  UINT8 *Dptr;

  DisplayPointer  = (PXE_T *) PxeTable;
  Dptr            = (UINT8 *) PxeTable;

  DEBUG ((DEBUG_NET, "This is the PXE table at address 0x%X\n\r", PxeTable));

  DEBUG ((DEBUG_NET, "A dump of the 0x%X bytes is:\n\r", sizeof (PXE_T)));

  for (Index = 0; Index < sizeof (PXE_T); Index++) {
    if ((Index % 0x10) == 0) {
      DEBUG ((DEBUG_NET, "\t\n\r"));
    }

    DEBUG ((DEBUG_NET, " 0x%X  ", *Dptr++));
  }

  DEBUG ((DEBUG_NET, "\n\r"));
  DEBUG (
    (DEBUG_NET,
    "\n\rPXE %c%c%c%c%c%c\n\r",
    DisplayPointer->Signature[0],
    DisplayPointer->Signature[1],
    DisplayPointer->Signature[2],
    DisplayPointer->Signature[3])
    );
  DEBUG (
    (DEBUG_NET,
    "Length of this structure in bytes = 0x%X\n\r",
    DisplayPointer->StructLength)
    );
  DEBUG (
    (DEBUG_NET,
    "Use to make byte checksum of this  structure == zero is = 0x%X\n\r",
    DisplayPointer->StructCksum)
    );
  DEBUG (
    (DEBUG_NET,
    "Structure format revision number = 0x%X\n\r",
    DisplayPointer->StructRev)
    );
  DEBUG (
    (DEBUG_NET,
    "Must be zero, is equal to 0x%X\n\r",
    DisplayPointer->Reserved1)
    );
  DEBUG (
    (DEBUG_NET,
    "Far pointer to UNDI ROMID = 0x%X\n\r",
    (UINT32) (DisplayPointer->Undi.Segment << 0x4 | DisplayPointer->Undi.Offset))
    );
  DEBUG (
    (DEBUG_NET,
    "Far pointer to base-code ROMID = 0x%X\n\r",
    (UINT32) ((DisplayPointer->Base.Segment << 0x04) | DisplayPointer->Base.Offset))
    );
  DEBUG ((DEBUG_NET, "16bit stack segment API entry point.  This will be seg:off in \n\r"));
  DEBUG (
    (DEBUG_NET,
    "real mode and sel:off in 16:16 protected mode = 0x%X:0x%X\n\r",
    DisplayPointer->EntryPointSP.Segment,
    DisplayPointer->EntryPointSP.Offset)
    );

  DEBUG ((DEBUG_NET, "\n\tNOTE to the implementer\n\tThis is the entry to use for call-ins\n\r"));

  DEBUG ((DEBUG_NET, "32bit stack Segment API entry point.  This will be sel:off. \n\r"));
  DEBUG (
    (DEBUG_NET,
    "In real mode, sel == 0 = 0x%X:0x%X\n\r",
    DisplayPointer->EntryPointESP.Segment,
    DisplayPointer->EntryPointESP.Offset)
    );
  DEBUG (
    (DEBUG_NET,
    "Reserved2 value, must be zero, is equal to 0x%X\n\r",
    DisplayPointer->Reserved2)
    );
  DEBUG (
    (DEBUG_NET,
    "Number of segment descriptors in this structur = 0x%X\n\r",
    (UINT8) DisplayPointer->SegDescCnt)
    );
  DEBUG (
    (DEBUG_NET,
    "First segment descriptor in GDT assigned to PXE = 0x%X\n\r",
    (UINT16) DisplayPointer->FirstSelector)
    );
  DEBUG (
    (DEBUG_NET,
    "The Stack is \n\r\tSegment Addr = 0x%X\n\r\tPhysical Addr = 0x%X\n\r\tSeg Size = 0x%X\n\r",
    (UINT16) DisplayPointer->Stack.Seg_Addr,
    (UINT32) DisplayPointer->Stack.Phy_Addr,
    (UINT16) DisplayPointer->Stack.Seg_Size)
    );
  DEBUG (
    (DEBUG_NET,
    "The UNDIData is \n\r\tSegment Addr = 0x%X\n\r\tPhysical Addr = 0x%X\n\r\tSeg Size = 0x%X\n\r",
    (UINT16) DisplayPointer->UNDIData.Seg_Addr,
    (UINT32) DisplayPointer->UNDIData.Phy_Addr,
    (UINT16) DisplayPointer->UNDIData.Seg_Size)
    );
  DEBUG (
    (DEBUG_NET,
    "The UNDICodeWrite is \n\r\tSegment Addr = 0x%X\n\r\tPhysical Addr = 0x%X\n\r\tSeg Size = 0x%X\n\r",
    (UINT16) DisplayPointer->UNDICode.Seg_Addr,
    (UINT32) DisplayPointer->UNDICode.Phy_Addr,
    (UINT16) DisplayPointer->UNDICode.Seg_Size)
    );
  DEBUG (
    (DEBUG_NET,
    "The Stack is \n\r\tSegment Addr = 0x%X\n\r\tPhysical Addr = 0x%X\n\r\tSeg Size = 0x%X\n\r",
    (UINT16) DisplayPointer->UNDICodeWrite.Seg_Addr,
    (UINT32) DisplayPointer->UNDICodeWrite.Phy_Addr,
    (UINT16) DisplayPointer->UNDICodeWrite.Seg_Size)
    );
  DEBUG (
    (DEBUG_NET,
    "The BC_Data is \n\r\tSegment Addr = 0x%X\n\r\tPhysical Addr = 0x%X\n\r\tSeg Size = 0x%X\n\r",
    (UINT16) DisplayPointer->BC_Data.Seg_Addr,
    (UINT32) DisplayPointer->BC_Data.Phy_Addr,
    (UINT16) DisplayPointer->BC_Data.Seg_Size)
    );
  DEBUG (
    (DEBUG_NET,
    "The BC_Code is \n\r\tSegment Addr = 0x%X\n\r\tPhysical Addr = 0x%X\n\r\tSeg Size = 0x%X\n\r",
    (UINT16) DisplayPointer->BC_Code.Seg_Addr,
    (UINT32) DisplayPointer->BC_Code.Phy_Addr,
    (UINT16) DisplayPointer->BC_Code.Seg_Size)
    );
  DEBUG (
    (DEBUG_NET,
    "The BC_CodeWrite is \n\r\tSegment Addr = 0x%X\n\r\tPhysical Addr = 0x%X\n\r\tSeg Size = 0x%X\n\r",
    (UINT16) DisplayPointer->BC_CodeWrite.Seg_Addr,
    (UINT32) DisplayPointer->BC_CodeWrite.Phy_Addr,
    (UINT16) DisplayPointer->BC_CodeWrite.Seg_Size)
    );
}

/**
  Print PXENV table.

  @param PxenvTable Point to PXENV

**/
VOID
Print_PXENV_Table (
  IN VOID *PxenvTable
  )
{
  PXENV_T *DisplayPointer;

  DisplayPointer = (PXENV_T *) PxenvTable;

  DEBUG (
    (DEBUG_NET,
    "\n\rPXENV+ %c%c%c%c%c%c\n\r",
    DisplayPointer->Signature[0],
    DisplayPointer->Signature[1],
    DisplayPointer->Signature[2],
    DisplayPointer->Signature[3],
    DisplayPointer->Signature[4],
    DisplayPointer->Signature[5])
    );

  DEBUG (
    (DEBUG_NET,
    "PXE version number.  \n\r\tLSB is minor version.  \n\r\tMSB is major version = 0x%X\n\r",
    DisplayPointer->Version)
    );
  DEBUG (
    (DEBUG_NET,
    "Length of PXE-2.0 Entry Point structure in bytes = 0x%X\n\r",
    DisplayPointer->StructLength)
    );
  DEBUG ((DEBUG_NET, "Used to make structure checksum equal zero is now = 0x%X\n\r", DisplayPointer->StructCksum));
  DEBUG ((DEBUG_NET, "Real mode API entry point  segment:Offset.  = 0x%X\n\r", DisplayPointer->RMEntry));
  DEBUG ((DEBUG_NET, "Protected mode API entry point = 0x%X\n\r", DisplayPointer->PMEntryOff));
  DEBUG ((DEBUG_NET, " segment:Offset.  This will always be zero.  \n\r"));
  DEBUG ((DEBUG_NET, "Protected mode API calls = 0x%X\n\r", DisplayPointer->PMEntrySeg));
  DEBUG ((DEBUG_NET, "Real mode stack segment = 0x%X\n\r", DisplayPointer->StackSeg));
  DEBUG ((DEBUG_NET, "Stack segment size in bytes = 0x%X\n\r", DisplayPointer->StackSize));
  DEBUG ((DEBUG_NET, "Real mode base-code code segment = 0x%X\n\r", DisplayPointer->BaseCodeSeg));
  DEBUG ((DEBUG_NET, "Base-code code segment size = 0x%X\n\r", DisplayPointer->BaseCodeSize));
  DEBUG ((DEBUG_NET, "Real mode base-code data segment = 0x%X\n\r", DisplayPointer->BaseDataSeg));
  DEBUG ((DEBUG_NET, "Base-code data segment size = 0x%X\n\r", DisplayPointer->BaseDataSize));

  DEBUG (
    (DEBUG_NET,
    "UNDI code segment size in bytes = 0x%X\n\r",
    DisplayPointer->UNDICodeSize)
    );
  DEBUG (
    (DEBUG_NET,
    "Real mode segment:Offset pointer \n\r\tto PXE Runtime ID structure, address = 0x%X\n\r",
    DisplayPointer->RuntimePtr)
    );
  DEBUG (
    (
    DEBUG_NET,
    "From above, we have a linear address of 0x%X\n\r",
    (UINT32)
    (
    ((UINT32)(UINTN)(DisplayPointer->RuntimePtr) & 0xFFFF) +
    (((UINT32)(UINTN)(DisplayPointer->RuntimePtr) & 0xFFFF0000) >> 12)
    )
    )
    );
}


#define OPTION_ROM_PTR  ((OPTION_ROM_HEADER *) RomAddress)

/**
  If available, launch the BaseCode from a NIC option ROM.
  This should install the !PXE and PXENV+ structures in memory for
  subsequent use.


  @param SimpleNetworkDevice    Simple network device instance
  @param RomAddress             The ROM base address for NIC rom.

  @retval EFI_NOT_FOUND         The check sum does not match
  @retval EFI_NOT_FOUND         Rom ID offset is wrong
  @retval EFI_NOT_FOUND         No Rom ID structure is found
**/
EFI_STATUS
LaunchBaseCode (
  EFI_SIMPLE_NETWORK_DEV  *SimpleNetworkDevice,
  UINTN                   RomAddress
  )
{
  EFI_STATUS            Status;
  EFI_IA32_REGISTER_SET InOutRegs;
  UNDI_ROMID_T          *RomIdTableAddress;
  UNDI_LOADER_T         *UndiLoaderTable;
  UINT16                Segment;
  UINT16                *StackPointer;
  VOID                  *Buffer;
  UINTN                 Size;
  PXE_T                 *Pxe;
  UINT32                RomLength;
  UINTN                 PciSegment;
  UINTN                 Bus;
  UINTN                 Device;
  UINTN                 Function;
  BOOLEAN               ThunkFailed;

  DEBUG ((DEBUG_NET, "\n\r\n\rCheck for the UNDI ROMID Signature\n\r"));

  //
  // paranoia - check structures for validity
  //
  RomLength = OPTION_ROM_PTR->ROMlength << 9;
  if (CalculateSum8 ((UINT8 *) RomAddress, RomLength) != 0) {
    DEBUG ((DEBUG_ERROR, "ROM Header Checksum Error\n\r"));
    return EFI_NOT_FOUND;
  }

  RomIdTableAddress = (UNDI_ROMID_T *) (RomAddress + OPTION_ROM_PTR->PxeRomIdOffset);

  if (((UINT32)OPTION_ROM_PTR->PxeRomIdOffset + RomIdTableAddress->StructLength) > RomLength) {
    DEBUG ((DEBUG_ERROR, "ROM ID Offset Error\n\r"));
    return EFI_NOT_FOUND;
  }
  //
  // see if this is a header for an UNDI ROM ID structure (vs. a $BC$ or BUSD type)
  //
  if (CompareMem (RomIdTableAddress->Signature, UNDI_ROMID_SIG, sizeof RomIdTableAddress->Signature) != 0) {
    DEBUG ((DEBUG_ERROR, "No ROM ID Structure found....\n\r"));
    return EFI_NOT_FOUND;
    //
    // its not - keep looking
    //
  }

  if (CalculateSum8 ((UINT8 *) RomIdTableAddress, RomIdTableAddress->StructLength) != 0) {
    DEBUG ((DEBUG_ERROR, "ROM ID Checksum Error\n\r"));
    return EFI_NOT_FOUND;
  }

  Print_ROMID_Table (RomIdTableAddress);

  DEBUG (
    (DEBUG_NET,
    "The ROM ID is located at 0x%X\n\r",
    RomIdTableAddress)
    );

  DEBUG (
    (DEBUG_NET,
    "With an UNDI Loader located at 0x%X\n\r",
    RomAddress + RomIdTableAddress->UNDI_Loader)
    );

  //
  // found an UNDI ROM ID structure
  //
  SimpleNetworkDevice->Nii.ImageAddr  = RomAddress;
  SimpleNetworkDevice->Nii.ImageSize  = RomLength;
  SimpleNetworkDevice->Nii.MajorVer   = RomIdTableAddress->UNDI_Rev[2];
  SimpleNetworkDevice->Nii.MinorVer   = RomIdTableAddress->UNDI_Rev[1];

  DEBUG ((DEBUG_NET, "Allocate area for the UNDI_LOADER_T structure\n\r"));
  //
  // Allocate 1 page below 1MB to put real mode thunk code in
  //
  // Undi Loader Table is a PXE Specification prescribed data structure
  // that is used to transfer information into and out of the Undi layer.
  // Note how it must be located below 1 MB.
  //
  SimpleNetworkDevice->UndiLoaderTablePages = EFI_SIZE_TO_PAGES (PARAGRAPH_SIZE + sizeof (UNDI_LOADER_T));
  Status = BiosSnp16AllocatePagesBelowOneMb (
            SimpleNetworkDevice->UndiLoaderTablePages,
            &SimpleNetworkDevice->UndiLoaderTable
            );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "We had a failure in AllocatePages, status code = 0x%X\n", Status));
    return EFI_OUT_OF_RESOURCES;
  }

  UndiLoaderTable = SimpleNetworkDevice->UndiLoaderTable;

  DEBUG ((DEBUG_NET, "Allocate area for the real-mode stack whose sole purpose\n\r"));
  DEBUG ((DEBUG_NET, "in life right now is to store a SEG:OFFSET combo pair that\n\r"));
  DEBUG ((DEBUG_NET, "points to an Undi_Loader_t table structure\n\r"));

  Size    = 0x100;
  Status  = gBS->AllocatePool (EfiLoaderData, Size, &Buffer);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Now we want to put a pointer to the Under Loader Table in our MemPage
  // Buffer.  This will be the argument stack for the call into the Undi Loader
  //
  StackPointer    = (UINT16 *) Buffer;
  *StackPointer++ = TO_OFFSET (UndiLoaderTable);
  //
  // push the OFFSET
  //
  *StackPointer++ = TO_SEGMENT (UndiLoaderTable);
  //
  // push the SEGMENT
  //
  StackPointer = (UINT16 *) Buffer;
  //
  // reset the stack pointer
  //
  DEBUG (
    (DEBUG_NET,
    "After the fixups, the stack pointer is 0x%X\n\r",
    (UINT64)(UINTN) StackPointer)
    );

  //
  // Allocate memory for the Deployed UNDI.
  // The UNDI is essentially telling us how much space it needs, and
  // it is up to the EFI driver to allocate sufficient, boot-time
  // persistent resources for the call
  //
  SimpleNetworkDevice->DestinationDataSegmentPages = EFI_SIZE_TO_PAGES (RomIdTableAddress->DataSize);
  Status = BiosSnp16AllocatePagesBelowOneMb (
            SimpleNetworkDevice->DestinationDataSegmentPages,
            &SimpleNetworkDevice->DestinationDataSegment
            );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "We had a failure in AllocatePages, status code = 0x%X\n", Status));
    return Status;
  }

  UndiLoaderTable->Undi_Ds = (UINT16) ((UINTN) SimpleNetworkDevice->DestinationDataSegment >> 4);

  //
  // Allocate memory for the Deployed UNDI stack
  // The UNDI is essentially telling us how much space it needs, and
  // it is up to the EFI driver to allocate sufficient, boot-time
  // persistent resources for the call
  //
  SimpleNetworkDevice->DestinationStackSegmentPages = EFI_SIZE_TO_PAGES (RomIdTableAddress->StackSize);
  Status = BiosSnp16AllocatePagesBelowOneMb (
            SimpleNetworkDevice->DestinationStackSegmentPages,
            &SimpleNetworkDevice->DestinationStackSegment
            );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "We had a failure in AllocatePages, status code = 0x%X\n", Status));
    return Status;
  }
  //
  // Allocate memory for the Deployed UNDI.
  // The UNDI is essentially telling us how much space it needs, and
  // it is up to the EFI driver to allocate sufficient, boot-time
  // persistent resources for the call
  //
  SimpleNetworkDevice->DestinationCodeSegmentPages = EFI_SIZE_TO_PAGES (RomIdTableAddress->CodeSize);
  Status = BiosSnp16AllocatePagesBelowOneMb (
            SimpleNetworkDevice->DestinationCodeSegmentPages,
            &SimpleNetworkDevice->DestinationCodeSegment
            );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "We had a failure in AllocatePages, status code = 0x%X\n", Status));
    return Status;
  }

  UndiLoaderTable->Undi_Cs = (UINT16) ((UINTN) SimpleNetworkDevice->DestinationCodeSegment >> 4);

  //
  // these are in the Input and Output Parameter to be sent to the UNDI Loader code
  //
  UndiLoaderTable->Status = 0xAA55;
  //
  // -------------------- Changed by Michael_Huang@3Com.com -----------------
  // UndiLoaderTable->_AX is AX value when UNDI ROM is initialized by BIOS, it is the PCI bus device
  // function of the NIC. Please refer to PXE Spec for detail info.
  // old code is:
  // UndiLoaderTable->Ax       = 0x0;
  // -----------------------------------------------------------------------
  //
  SimpleNetworkDevice->PciIo->GetLocation (
                                SimpleNetworkDevice->PciIo,
                                &PciSegment,
                                &Bus,
                                &Device,
                                &Function
                                );
  UndiLoaderTable->Ax = (UINT16) ((Bus << 0x8) | (Device << 0x3) | (Function));
  UndiLoaderTable->Bx = 0x0;
  UndiLoaderTable->Dx = 0x0;
  UndiLoaderTable->Di = 0x0;
  UndiLoaderTable->Es = 0x0;

  //
  // set these OUT values to zero in order to ensure that
  // uninitialized memory is not mistaken for display data
  //
  UndiLoaderTable->PXEptr.Offset    = 0;
  UndiLoaderTable->PXEptr.Segment   = 0;
  UndiLoaderTable->PXENVptr.Segment = 0;
  UndiLoaderTable->PXENVptr.Offset  = 0;

  DEBUG (
    (DEBUG_INIT,
    "The NIC is located at Bus 0x%X, Device 0x%X, Function 0x%X\n\r",
    Bus,
    Device,
    Function)
    );

  //
  // These are the values that set up the ACTUAL IA32 machine state, whether in
  // Real16 in EFI32 or the IVE for IA64
  // register values are unused except for CS:IP and SS:SP
  //
  InOutRegs.X.AX  = 0;
  InOutRegs.X.BX  = 0;
  InOutRegs.X.CX  = 0;
  InOutRegs.X.DX  = 0;
  InOutRegs.X.SI  = 0;
  InOutRegs.X.DI  = 0;
  InOutRegs.X.BP  = 0;
  InOutRegs.X.DS  = 0;
  InOutRegs.X.ES  = 0;
  //
  // just to be clean
  //
  DEBUG ((DEBUG_NET, "The way this game works is that the SS:SP +4 should point\n\r"));
  DEBUG ((DEBUG_NET, "to the contents of the UndiLoaderTable\n\r"));
  DEBUG (
    (DEBUG_NET,
    "The Undi Loader Table is at address = 0x%X\n\r",
    (UINT32)(UINTN) UndiLoaderTable)
    );
  DEBUG (
    (DEBUG_NET,
    "The segment and offsets are 0x%X and 0x%X, resp\n",
    TO_SEGMENT (UndiLoaderTable),
    TO_OFFSET (UndiLoaderTable))
    );

  DEBUG (
    (DEBUG_NET,
    "The Linear Address of the UNDI Loader entry is 0x%X\n",
    RomAddress + RomIdTableAddress->UNDI_Loader)
    );

  DEBUG (
    (DEBUG_NET,
    "The Address offset of the UNDI Loader entry is 0x%X\n",
    RomIdTableAddress->UNDI_Loader)
    );

  DEBUG ((DEBUG_NET, "Before the call, we have...\n\r"));
  Print_Undi_Loader_Table (UndiLoaderTable);

  Segment = ((UINT16) (RShiftU64 (RomAddress, 4) & 0xFFFF));
  DEBUG ((DEBUG_NET, "The Segment of the call is 0x%X\n\r", Segment));

  //
  // make the call into the UNDI Code
  //
  DEBUG ((DEBUG_INIT, "Make the call into the UNDI code now\n\r"));

  DEBUG ((DEBUG_NET, "\nThe 20-BIt address of the Call, and the location \n\r"));
  DEBUG ((DEBUG_NET, "\twhere we should be able to set a breakpoint is \n\r"));
  DEBUG (
    (DEBUG_NET,
    "\t\t0x%X, from SEG:OFF 0x%X:0x%X\n\r\n\r",
    Segment * 0x10 + RomIdTableAddress->UNDI_Loader,
    Segment,
    RomIdTableAddress->UNDI_Loader)
    );

  ThunkFailed = SimpleNetworkDevice->LegacyBios->FarCall86 (
                                                   SimpleNetworkDevice->LegacyBios,
                                                   Segment,  // Input segment
                                                   (UINT16) RomIdTableAddress->UNDI_Loader,  // Offset
                                                   &InOutRegs,                               // Ptr to Regs
                                                   Buffer,                                   // Reference to Stack
                                                   Size                                      // Size of the Stack
                                                   );
  if (ThunkFailed) {
    return EFI_ABORTED;
  }

  DEBUG (
    (DEBUG_NET,
    "The return code UndiLoaderTable->Status is = 0x%X\n\r",
    UndiLoaderTable->Status)
    );
  DEBUG (
    (DEBUG_NET,
    "This error code should match eax, which is = 0x%X\n\r",
    InOutRegs.X.AX)
    );

  if ((UndiLoaderTable->Status != 0) || (InOutRegs.X.AX != PXENV_EXIT_SUCCESS)) {
    DEBUG ((DEBUG_NET, "LaunchBaseCode exits with error, RomAddress = 0x%X\n\r", RomAddress));
    return EFI_ABORTED;
  }

  DEBUG ((DEBUG_NET, "Now returned from the UNDI code\n\r"));

  DEBUG ((DEBUG_NET, "After the call, we have...\n\r"));
  Print_Undi_Loader_Table (UndiLoaderTable);

  DEBUG ((DEBUG_NET, "Display the PXENV+ and !PXE tables exported by NIC\n\r"));
  Print_PXENV_Table ((VOID *)(((UINTN)UndiLoaderTable->PXENVptr.Segment << 4) | UndiLoaderTable->PXENVptr.Offset));
  Print_PXE_Table ((VOID *)(((UINTN)UndiLoaderTable->PXEptr.Segment << 4) + UndiLoaderTable->PXEptr.Offset));

  Pxe = (PXE_T *)(((UINTN)UndiLoaderTable->PXEptr.Segment << 4) + UndiLoaderTable->PXEptr.Offset);
  SimpleNetworkDevice->Nii.Id = (UINT64)(UINTN) Pxe;

  gBS->FreePool (Buffer);

  //
  // paranoia - make sure a valid !PXE structure
  //
  if (CompareMem (Pxe->Signature, PXE_SIG, sizeof Pxe->Signature) != 0) {
    DEBUG ((DEBUG_ERROR, "!PXE Structure not found....\n\r"));
    return EFI_NOT_FOUND;
    //
    // its not - keep looking
    //
  }

  if (CalculateSum8 ((UINT8 *) Pxe, Pxe->StructLength) != 0) {
    DEBUG ((DEBUG_ERROR, "!PXE Checksum Error\n\r"));
    return EFI_NOT_FOUND;
  }

  if (Pxe->StructLength < (UINT8 *) &Pxe->FirstSelector - (UINT8 *) Pxe->Signature) {
    DEBUG ((DEBUG_ERROR, "!PXE Length Error\n\r"));
    return EFI_NOT_FOUND;
  }

  if ((((UINTN) Pxe->Undi.Segment) << 4) + Pxe->Undi.Offset != (UINTN) RomIdTableAddress) {
    DEBUG ((DEBUG_ERROR, "!PXE RomId Address Error\n\r"));
    return EFI_NOT_FOUND;
  }
  //
  // This is the magic to bind the global PXE interface
  // This dirtiness is for non-protocol shrouded access
  //
  SimpleNetworkDevice->PxeEntrySegment = Pxe->EntryPointSP.Segment;

  if (SimpleNetworkDevice->PxeEntrySegment == 0) {
    DEBUG ((DEBUG_ERROR, "!PXE EntryPointSP segment Error\n\r"));
    return EFI_NOT_FOUND;
  }

  SimpleNetworkDevice->PxeEntryOffset = Pxe->EntryPointSP.Offset;

  DEBUG (
    (
    DEBUG_NET, "The entry point is 0x%X:0x%X\n\r", SimpleNetworkDevice->PxeEntrySegment, SimpleNetworkDevice->
    PxeEntryOffset
    )
    );

  return EFI_SUCCESS;
}

/**
  Effect the Far Call into the PXE Layer

  Note: When using a 32-bit stack segment do not push 32-bit words onto the stack. The PXE API
  services will not work, unless there are three 16-bit parameters pushed onto the stack.
      push DS                                 ;Far pointer to parameter structure
      push offset pxe_data_call_struct        ;is pushed onto stack.
      push Index                              ;UINT16 is pushed onto stack.
      call dword ptr (s_PXE ptr es:[di]).EntryPointSP
      add sp, 6 ;Caller cleans up stack.

  @param SimpleNetworkDevice    Device instance for simple network
  @param Table                 Point to parameter/retun value table for legacy far call
  @param TableSize              The size of parameter/return value table
  @param CallIndex              The index of legacy call.

  @return EFI_STATUS
**/
EFI_STATUS
MakePxeCall (
  EFI_SIMPLE_NETWORK_DEV  *SimpleNetworkDevice,
  IN OUT VOID             *Table,
  IN UINTN                TableSize,
  IN UINT16               CallIndex
  )
{
  EFI_STATUS            Status;
  EFI_IA32_REGISTER_SET InOutRegs;
  UINT16                *BPtr;
  VOID                  *Buffer;
  UINTN                 Size;
  VOID                  *MemPageAddress;
  UINTN                 Index;
  BOOLEAN               ThunkFailed;

  DEBUG ((DEBUG_NET, "MakePxeCall(CallIndex = %02x, Table = %X, TableSize = %d)\n", CallIndex, Table, TableSize));

  if (SimpleNetworkDevice->PxeEntrySegment == 0 && SimpleNetworkDevice->PxeEntryOffset == 0) {
    return EFI_DEVICE_ERROR;
  }

  Status = EFI_SUCCESS;

  //
  // Allocate a transient data structure for the argument table
  // This table needs to have the input XXX_t structure copied into here.
  // The PXE UNDI can only grab this table when it's below one-MB, and
  // this implementation will not try to push this table on the stack
  // (although this is a possible optimization path since EFI always allocates
  // 4K as a minimum page size...............)
  //
  Status = BiosSnp16AllocatePagesBelowOneMb (
            TableSize / EFI_PAGE_SIZE + 1,
            &MemPageAddress
            );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "We had a failure in AllocatePages, status code = 0x%X\n", Status));
    return Status;
  }
  //
  // Copy the > 1MB pool table to a sub-1MB buffer
  //
  CopyMem (MemPageAddress, Table, TableSize);

  //
  // Allocate space for IA-32 register context
  //
  ZeroMem (&InOutRegs, sizeof (InOutRegs));
  InOutRegs.X.ES  = SimpleNetworkDevice->PxeEntrySegment;
  InOutRegs.X.DI  = SimpleNetworkDevice->PxeEntryOffset;

  //
  // The game here is to build the stack which will subsequently
  // get copied down below 1 MB by the FarCall primitive.
  // This is now our working stack
  //
  Size = 6;
  Status = gBS->AllocatePool (
                  EfiRuntimeServicesData,
                  Size,
                  &Buffer
                  );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  BPtr    = (UINT16 *) Buffer;
  *BPtr++ = CallIndex;
  //
  // SP + 2
  //
  *BPtr++ = TO_OFFSET (MemPageAddress);
  *BPtr++ = TO_SEGMENT (MemPageAddress);

  DEBUG ((DEBUG_NET, "State before FarCall86\n"));
  DEBUG ((DEBUG_NET, "The Buffer is at 0x%X\n\r", Buffer));
  BPtr = (UINT16 *) Buffer;
  DEBUG ((DEBUG_NET, "  Buffer  = %04X %04X %04X", *BPtr, *(BPtr + 1), *(BPtr + 2)));
  DEBUG ((DEBUG_NET, "  MemPage = "));
  for (Index = 0; Index < TableSize; Index++) {
    DEBUG ((DEBUG_NET, " %02x", *((UINT8 *) MemPageAddress + Index)));
  }

  DEBUG ((DEBUG_NET, "\n"));

  ThunkFailed = SimpleNetworkDevice->LegacyBios->FarCall86 (
                                                   SimpleNetworkDevice->LegacyBios,
                                                   SimpleNetworkDevice->PxeEntrySegment, // Input segment
                                                   SimpleNetworkDevice->PxeEntryOffset,
                                                   &InOutRegs,                           // Ptr to Regs
                                                   Buffer,                               // Reference to Stack
                                                   6                                     // Size of the Stack
                                                   );
  if (ThunkFailed) {
    return EFI_ABORTED;
  }

  DEBUG ((DEBUG_NET, "State after FarCall86\n"));
  DEBUG ((DEBUG_NET, "The Buffer is at 0x%X\n\r", Buffer));
  BPtr = (UINT16 *) Buffer;
  DEBUG ((DEBUG_NET, "  Buffer  = %04X %04X %04X", *BPtr, *(BPtr + 1), *(BPtr + 2)));
  DEBUG ((DEBUG_NET, "  MemPage = "));
  for (Index = 0; Index < TableSize; Index++) {
    DEBUG ((DEBUG_NET, " %02x", *((UINT8 *) MemPageAddress + Index)));
  }

  DEBUG ((DEBUG_NET, "\n"));

  //
  // Copy the sub 1MB table to > 1MB table
  //
  CopyMem (Table, MemPageAddress, TableSize);

  //
  // For PXE UNDI call, AX contains the return status.
  // Convert the PXE UNDI Status to EFI_STATUS type
  //
  if (InOutRegs.X.AX == PXENV_EXIT_SUCCESS) {
    Status = EFI_SUCCESS;
  } else {
    Status = EFI_DEVICE_ERROR;
  }
  //
  // Clean up house
  //
  gBS->FreePool (Buffer);
  gBS->FreePages ((EFI_PHYSICAL_ADDRESS) (UINTN) MemPageAddress, TableSize / EFI_PAGE_SIZE + 1);

  return Status;
}
